#include "mpi.h" int MPI_Init(argc,argv) int *argc; char ***argv;
mem - Enable dynamic memory tracing of internal MPI objects memall - Generate output of all memory allocation/deallocation ptr - Enable tracing of internal MPI pointer conversions rank n - Limit subsequent -mpidb options to on the process with the specified rank in MPI_COMM_WORLD. A rank of -1 selects all of MPI_COMM_WORLD. ref - Trace use of internal MPI objects reffile filename - Trace use of internal MPI objects with output to the indicated file trace - Trace routine calls
Because the Fortran and C versions of MPI_Init are different, there isa restriction on who can call MPI_Init. The version (Fortran or C) mustmatch the main program. That is, if the main program is in C, thenthe C version of MPI_Init must be called. If the main program is inFortran, the Fortran version must be called.
On exit from this routine, all processes will have a copy of the argumentlist. This is not required by the MPI standard, and truely portable codesshould not rely on it. This is provided as a service by thisimplementation (an MPI implementation is allowed to distribute thecommand line arguments but is not required to).
Command line arguments are not provided to Fortran programs. Moreprecisely, non-standard Fortran routines such as getarg and iargchave undefined behavior in MPI and in this implementation.
The MPI standard does not say what a program can do before an MPI_INIT orafter an MPI_FINALIZE. In the MPICH implementation, you should doas little as possible. In particular, avoid anything that changes theexternal state of the program, such as opening files, reading standardinput or writing to standard output.
Note that if you are using software that needs the same signals, you mayfind that there is no way to use that software with the MPI implementation. The signals that cause the most trouble for applications includeSIGIO, SIGALRM, and SIGPIPE. For example, using SIGIO andSIGPIPE may prevent X11 routines from working.
All MPI routines (except MPI_Wtime and MPI_Wtick) return an error value; C routines as the value of the function and Fortran routines in the lastargument. Before the value is returned, the current MPI error handler iscalled. By default, this error handler aborts the MPI job. The error handlermay be changed with MPI_Errhandler_set; the predefined error handlerMPI_ERRORS_RETURN may be used to cause error values to be returned. Note that MPI does not guarentee that an MPI program can continue pastan error.